1. Field of the Invention
The invention relates to a pressurized device for the dispensing of liquid or creamy products, for example, cosmetic, food or pharmaceutical products. 2. Description of the Related Art A conventional pressurized device is constituted by a container body on which a lid is optionally fitted. A valve is crimped on the neck of the container by means of a valve carrier cup. A dispensing means is connected to the valve. The container body and the cup define a reservoir cavity. The valve is constituted by a valve body, a valve actuating stem that passes through the valve body, a gasket, and a restoring system that applies the valve actuating stem against the gasket, the unit being kept in position by the crimping of the valve carrier cup. The valve actuating stem is surmounted by a push button. A product to be dispensed and a propellant are disposed in the reservoir cavity.
The propellant may be a compressed gas directly in contact with the product in the container body. In this case, a dip tube element is fixed to the valve. When it is not desirable for the product to be in contact with the gas, provision may be also made for separating the gas and the product by a flexible pouch or by a piston. In the case of the flexible pouch, problems frequently arise concerning compatibility with the formula and strength the material constituting the pouch which must be flexible and leakproof In the case where a piston is used for separating the gas from the product, there arise sealing problems along the contact surfaces between the piston and the internal wall of the container body.
Moreover, in these two cases, the fill opening for the gas must be distinct from that for the formula: filling with gas is frequently undertaken through an opening situated at the bottom of the container, obturated by a rubber stopper. This configuration requires repetitive actions during manufacture: opening the gas fill opening, positioning the pouch or the piston, and positioning the stopper. It is also expensive because of the complexity of the filling process: feeding first the product and then the gas.
Moreover, from EP-A-0561292, dispensing devices are known which use as the propellant a cellular material with closed cells. A gas is trapped in the cells of the cellular material. This document describes devices in which the product is placed into a flexible bottle inside the container body. The cellular material is placed into this container body in contact with, and outside, the flexible bottle. The cellular material is connected to a knurled wheel. Before actuating the valve by means of a push button, the user must store energy in the cellular material by actuating the knurled wheel. The gas contained in the cellular material is then subjected to mechanical pressure and transmits this pressure to the bottle and its contents: by actuating the valve, the product can then be dispensed.
However, such a device has several drawbacks: this device has a large number of parts. These parts require very fine adjustment (screw threads, seal) and are sophisticated. As a result, this device is very expensive. The storage of energy by mechanical compression of the cellular material is effected in small quantities: before actuating the push button, the user must turn the knurled wheel to store the energy corresponding to approximately one application dose. The need for this double action renders the device complicated and unattractive for a consumer in a hurry. The bottle wherein the product is contained has the shape of a bellows. Thus, even if it is compressed to a maximum by the action of the cellular material, this bottle cannot be completely emptied and a low recovery rate is obtained.
When the user stores energy in the cellular material by turning the knurled wheel, he creates a strong osmotic pressure on either side of the bottle. Thus the wall of this bottle, subjected to a to and fro motion by the mechanical action of the celular material, becomes fragile by frequent use. With this device, as in the case where a flexible pouch is used for separating a gas from the product, the same problem of compatibility of the product with the wall of the bottle is encountered. Moreover, if the user inadvertently exerts too powerful an action on the knurled wheel, he subjects the cellular material to a pressure which causes the cells containing the gas to burst, and irreversibly damages the device. Finally, such a device does not allow the bottle to be refilled with the product by means of the valve by pressurizing the cellular material since, by this mechanical compression, one would also obtain a bursting of the cells and would thus render the device no longer usable.